| A | B |
|---|
| soil | loose rock material that covers much of Earth's land surface and has three layers |
| gully | miniature river valleys |
| natural resource | any useful material from Earth |
| conservation | the wise use of natural resources |
| strip cropping | the planting of cover crops in strips between rows of crops |
| terracing | the building of steplike rdiges |
| contour plowing | plowing hilly land in a way that follows the shape of the land |
| dam building | building a dam to stop the flow of water and formation of gullies |
| ore | a rock that is mined for its minerals |
| rock | a solid material made up of one or more minerals |
| mineral | a natural solid that has a definate chemical makeup |
| nonrenewable resource | a resource that cannot be replaced |
| renewable | a resource that can be replaced |
| fossil fuels | coal, natural gas, and oil |
